That's the problem. There are too many Linux distributions to 'support'. From a developer standpoint. I have to 'define Linux support' and need to draw the line somewhere and pick a Linux distro and write a guide for it.
Several people will ask if their distro is also supported and another one will ask, followed by another one with the same question and then you would be updating more than 10 troubleshooting guides and maintaining more than 10 CIs for 'official' support. That's very expensive and this is why you cannot target 'all' Linux users.
On the other hand, I can support all Windows users 100% of the time. Same thing with macOS, and Haiku also has little to no fragmentation and that means I can give 1 CI per OS. Not 10 or 20. Even Redox gets it right with the same idea.
It's nice to see an open-source OS for once that has a sane desktop, usable software and is unified just like Windows and macOS.